This invention relates to methods and apparatus for automated article handling, and particularly concerns a method and apparatus for debagging articles such as can ends and the like.
Two-piece and three-piece can-type containers are widely used for packaging beverages, food products, petroleum products and a great number of other products. In the packaging of these products, it is common to provide the packaging machinery with a supply of can bodies and with a separate supply of pre-formed can ends. In many applications, and particularly in beverage packaging, it is common to provide a can end with a pull tab closure for ease of opening by the consumer.
The can ends are usually provided to the packaging machinery stacked in facewise relation in elongated stacks or groups, each of a predetermined and controlled number. These stacks are usually delivered to the packaging plant in elongated kraft paper bags which protect the can ends against dirt and contamination during handling and transport.
The packaging and closure activity occurs at a relatively high rate of speed, as high as perhaps hundreds of containers being filled and having their closures or ends applied per minute. As such, it is necessary to provide a large number of can ends at a relatively high speed. Advantageously, an effectively endless supply of can ends can be provided by a rotary or carousel type infeed or feeder unit or device of the type generally shown and described in U.S. Pat. No. 3,722,741 which is commonly owned herewith. The carousel type infeed unit shown in this U.S. patent employs a plurality of individual pockets for receiving and storing individual stacks of ends preparatory to delivery of the ends to the filling and closure machinery.
Before the stacks of can ends can be supplied to the filling and closure machinery, the kraft paper bags must be removed. The removal of these bags has heretofore been accomplished by hand, in that a bag of ends is placed in a pocket of the rotary infeed unit and the bag is then manually stripped from the stack of can ends. One previous mechanical device for automatically debagging stacks of can ends is shown in U.S. Pat. No. 4,245,946. Another device for automatically debagging can ends is shown in U.S. Pat. Nos. 4,580,938 and 4,681,507 which are commonly owned herewith. However, there remains room for yet further improvement.
In particular, it is desirable to provide a debagging method and apparatus can readily be employed with, and preferably retrofitted to, existing carousel or rotary-type infeed units of the type mentioned above, and as described in U.S. Pat. No. 3,722,741, without requiring modification to the carousel or rotary-type infeed unit.
One particular problem which arises when removing the elongated kraft paper bags from stacks of can ends is that of movement of one or more of the can ends out of their facewise stacked condition. More particularly, there is a tendency for the topmost end or ends of the stack to be tilted, canted or even completely flipped over during removal of the bag. This is due to frictional engagement of the topmost ends with the bag as the bag is pulled in an axial direction for removal. In particular, as the open end portion of the bag clears the topmost ends of the stack, there is a tendency of these topmost ends to be frictionally engaged by the end part of the bag to such an extent that they can be tilted, canted or actually flipped over 180.degree..
This condition is to be avoided, as the feeding of a reversely oriented can end to the filling and closure machinery can disrupt the highly automated, high speed filling and closure operation. Such disruptions or delays can be quite costly in terms of downtime of relatively large, highly automated lines. Moreover, when one piece of equipment in such an automated system must be shut down, other related equipment in the system often must also be shut down until the problem is corrected. Such delays are to be avoided as they are expensive in terms of the shutdown time of the equipment and of the overall packaging operation.